CMS Pixel MechanicalFPIX Half Disk Design Updates

C. M. Lei

Joe Howell

Kirk Arndt

Simon Kwan

November 8, 2011

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FPIX Half Disk Layout Requirements

1. Fits within Phase 1 FPIX envelope definition2. Only 2x8 modules are used all oriented radially (resolution slightly improves

compared to the layout of the current detector)3. Locates all outer radius sensors as far forward and out in radius as possible

(to minimize the gap in 4-hit coverage between the end of the 4th-barrel layer and the forward-most disk)

4. Maximize 4-hit coverage between end of 4th layer barrel up to eta = 2.5, for particles originating at the IP +/-5cm, using a minimum number of modules

5. Keep the same 20 degree tilt as the current detector6. Individual modules to be removable and replaceable without disassembling

other modules on the disks7. Identical substrates 8. Minimizes the amount of material required for CO2 cooling and module

support 9. Delta T < 5oC across a single module and < 14oC from coolant to sensor10. Separate inner and outer ring assemblies for easier replacement of

modules on the inner ring

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FPix Phase 1 Upgrade Plans

Baseline: 3 half-disks in each half-cylinder

Use only ONE kind of module 2x8, and ONE identical blade. • All modules are arranged radially and placed between r=45mm to

161mm (total 56 modules per half disk or 896 ROCs)• Modules divided into an outer ring of 34 modules and inner ring of

22 modules• Keep the same 20o rotation but for the inner assembly, add a 12o tilt

to the IP (inverted cone geometry)

C02 cooling: Use thin-walled SS tubing 316 L and the size is tentatively

chosen (1.638 mm OD, 1.435 mm ID).

Use ultra light weight materials for mechanical support and cooling (aim at material reduction of about a factor of 2)

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291396

η = 1.3 η = 1.6

η = 2.1

η = 2.5

2x8s 2x8s 2x8s

Z loc. TBD shown 491mm from IP

161

45

2x8s 2x8s 2x8s

Based on Morris Swartz’s study, it’s possible to optimize the layout to obtain excellent resolution in both the azimuthal and radial directions throughout the FPix acceptance angle since we have separate inner and outer blade assemblies.

Inverted cone array combined with the 20o Rotated Vanes for the inner blade.

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Basic Design of the Pixel Blade

• Solid TPG (0.68 mm thick, highly thermally conductive with in-plane k = 1500 W/mK) encapsulated with carbon-fiber facing (0.06 mm thick).

• Extra layer of carbon-fiber at blade ends with 45o cut.

• Cooling is arranged at the ends of the blade which is structurally and thermally bonded to cooling rings.

• All blades are identical with one module on each side. (Only 2x8 module is used.)

• Modules, which are glued with holders at ends, are removable.

• Aluminum threaded inserts are glued on blade for module mounting.

• One module holder provides cable strain-relief for the flex cable.

Threaded insert

Through holes to access screws of neighboring blades

Removable module assembly

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Basic Design of the Half Disk

• Half disk consists of one inner and one outer blade assembly.

• Both assemblies are fastened to the half cylinder individually with 3 mounts.

• Outer blade assembly consists of 17 blades.

• Inner blade assembly, with an inverted cone layout, consists of 11 blades.

• All blades are bonded to 2 half rings that act as heat sinks.

• Each bonded assembly can be mechanically/thermally tested as a unit prior to mounting modules.

Bonded Outer Ring Assemblyready to take modules

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Outer Blade Assembly

17 blades with Y-rotation 20o and Z offset = 2.5 mm, arranged in 2 rowsClosest distance between neighboring blades ~5.5 mm

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Inner Blade Assembly

11 blades with Y-rotation 20o, X-tilt 12o and Z offset = 4.5 mm, arranged in 2 rowsClosest distance between neighboring blades =~5 mm

Inner ring supporting spokes

Elevated tabs for blade gluing

Inverted cone layout

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M2 screw

Washer with spherical surface

Insert with conical surface

Insert with M2 threads

Outer and Inner Mount Assemblies Designs• spherical washer concept employed• a proven design for minor angular misalignment• reinforcement inserts are glued to CC ring for stronger support• assemblies can be removed separately

Washer with spherical surface

Insert with conical surface

Insert with #3-48 threads

M2 screw

Cf tubing

Rivet with #3-48 threads

Outer Assembly Mounts X3

Inner Assembly Mounts X3

SS Tubing Coupling X6

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Inner Ring Mount AssemblyOuter Ring Mount Assembly

Half Disks within Half Cylinder

Outer Assembly Mount

Inner Assembly Mount

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2 mm X 20 mm cable slot

Simple Cooling Arrangement

1.634 mm OD ss tubing

A simple C-C heat sink in a half ring shape is feasible (thermal k of C-C = ~ 200W/m-K)A simple and easy-to-fabricate ss tubing is embeddedStructural CF facing is glued to cover the tubing/cooling channelAll the curved-end surfaces of TPG blades are bonded to the surface of CC rings

C-C ring

cf facing

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Cooling Tubing Layout … (Lately Proposed)

• diagram of 3 (nearly identical) cooling loops in a half-cylinder segmentation of cooling follows segmentation of electronics

• 1 loop per half-disk = 6 loops per full cylinderNext steps:

a) Revise routing within the CC rings and half disk as neededb) Calculate the fluid temperature and pressure drop for each of the

cooling loops within a half cylinderc) Decide how to merge 6 (inlet and outlet) HC loops into 4 inlet and 4

outlet copper tubes to/from the plant

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Cooling Tubing Layout … (Lately Proposed - continued)

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The 3 cooling tube supply lines need to be routed in this section to make thermal connections to POH on

the port cards

The 3 cooling tube supply lines need to be routed in a serpentine path in this section to cool

the DC-DC converters

Port CardsDC-DC

Converters

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Trough # 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 total

Outer Inner Tubing 3 3 6Outer Outer Tubing 6* 6

Inner Tubing 6 6Outer Cable 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 1 34Inner Cable 1 2 2 2 2 2 2 2 2 2 2 1 22

* Tubing located inside HC beyond the trough

Cooling tube and flex cable routing are allowed installation/removal of the inner assemblies possible between previously installed outer assemblies

Half Disks with its cooling tubes and cables are installed in the order of 1st, 2nd and 3rd for outer assemblies first then 3rd, 2nd, 1st for the inner assemblies

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Filled with cf in transition section - enhance stiffness - increase surface area for gluing

Thin, front section with 27 troughs cooling tubes and cables of the inner assemblies can be removed from the outside of the HC, while outer assembly tubes and cables are kept inside the HC

All carbon-fiber reinforced plastic design consisting of 3 sections: - front corrugated single-wall section (1 mm thick) - transition section where front and rear sections are glued together - rear section (which is basically the same as the existing design)

rear section (shorten)

transition section

front section

Note: only a short length of rear section is shown

Conceptual Design of Half Cylinder

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• FEA as an aid for designing the front and transition regions (results for the rear section suppressed)• Used shell elements to model the trough profile through all length, except the transition region with solid elements.• Applied constraints on 4 support leg positions, with 2 top supports allowing downward displacement.• Half disk loads of 3.9 N each applied at 3 spots, no distributed load along the rear section.• 3 beam “spokes” simulate half disks that help to retain a circular profile

Preliminary FEA of Half Cylinder

Front End SupportRear End Support

Note: Rigid elements were used for proper model connectivity between solid and shell elements.

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Front Shell Thickness, mm

Cf strip at front thickness, mm

Max Deflection, mm

0.5 0.0 0.233

0.5 0.5 0.216

0.75 0.0 0.112

0.8 0.0 0.100

0.8 0.5 0.099

0.8 0.8 0.099

1.0 0.8 0.069

Max displacements in x, y, z -0.028, -0.059, -0.020 mm

4-Blade Thermal Testing Assembly

• Use this test to verify the overall temperature drop experimentally from the CO2 coolant to module (Goal: to be within 10oC with a heat load of 3W per module, agreed upon at the last CMS Tracker Upgrade Mechanics/Cooling Meeting as the cooling performance specification for the design)

• 4 TPG blades will be bonded to 2 CC ring segments

• Dummy 2x8 modules will be glued to blades

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Thermally Interface Materials (TIMs) Needed in this Test

1. Module on blade >> thermally conductive grease

2. Blade on CC half ring >> structural and thermally conductive adhesive

3. SS tubing within CC groove >> thermally conductive fillers/adhesive

4. CF facing on CC half ring >> structural adhesive

Note: Need to carefully select the TIMs 1, 2 and 3 for the testing. Thermal conductivities of these TIMs are preferred to be > 1 W/mK.

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TIMs Study and Lab-Testing Results

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Tested Tested Claimed Claimed

thicknessbulk

densitytemperat

urespecific

heat diffusivity conductivity resistance conductivity resistance

@ 25°C r @

25°C cp a l R l R

Sample   (mm)   (g/cm3)   (°C)   (J/g-K) (mm2/s) (W/m-K) (mm2-K/W) (W/m-K) (mm2-K/W)

 

EG7659 0.714 2.21 25 0.731 0.838 1.35   - 11.40 -

     

C-C substrate 1.76 1.82 25 0.733 238 319   5.53 200 -

     

CGL7019-LB 0.030 2.0 25 1.0 0.167 0.334   89.8 20.0 3.0

     

TPCM583 0.070 2.5 25 0.8 2.04 4.08   17.1 4.00 1.2

     

Duralco 135 0.067 2.7 25 0.8 0.525 1.13   59.0 5.80 -

     

Dow TC-5600 0.093 2.7 25 0.8 2.91 6.28   14.8 7.10 4.0

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TIMs Selection Status

• Module on blade Laird’s TPCM 583 or Dow Corning’s TC-5600 are OK

• Blade on C-C half ringAiT’s EG7659 is barely OKTry other adhesivesTry indium bonding

• SS tubing within CC groove Dow Corning’s TC-5600 appears OK

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Indium Bonding• An interface metallic material with high thermal conductivity and

low melting point• Only works for metal-to-metal surface; noble metal coating(s) like

gold, silver, nickel needed for bonding graphite• Other layer(s) to act as a diffusion barrier to achieve strong inter-

metallic bonds may be needed.• Oxidization of metal surface interferes with the wetting capability

flux can be used to improve wetting• Several alloys available

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Indium Bonding R&D

Indium #1E

Heated Platform

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Goal: To demonstrate the cut-end of the encapsulated TPG can be bonded to carbon-carbon surface

• Indium alloy used: #1E • Thermal k = 34 W/m-K• Tensile strength = 1,720 psi• X0 = 1.22 cm

Status:o carbon-carbon surface

• 5 micron thick silver were successfully coated

• Indium #1E wetted this surface wello TPG cut-end surface which consists of carbon-

fiber facing and TPG core• 5 micron thick silver was successfully

coated• these silvered coated parts could be

bonded together• joint was not strong enough• silver layer easily detached from TPG

surfaceFuture R&Do Add diffusion barrier(s)

• C + Ni + Ag + In  • C+ Ti + W + Ag + In

Half Disk Material Budget

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Half Disk Material Budget according to conceptual design November 2011 1832.39 vol of .8mm t blade with step at endsAll masses are distribued evenly over an effective overlapped substrate area = 5343 mm^2 (15o coverage) (15o coverage) (15o coverage) 

material t or L, mm area, mm^2 vol, mm^3 half disk q'tyhalf disk vol,

mm^3 half disk mass, g15-deg vol,

mm^3 density, g/cc Mass, gX0,

g/cm^2 Eff. % Rad LROC silicon 0.15 80 12 896 10701 24.9 892 2.33 2.078 21.9 0.18%Sensor silicon 0.25 1245 311 56 17432 40.6 1453 2.33 3.385 21.9 0.29%Sub-Total % RL 0.47%  TPG TPG 0.680 2290 1557 28 43602 98.5 3633 2.26 8.212 42.7 0.36%CF facing CF 0.120 2290 275 28 7694 13.5 641 1.76 1.129 42.8 0.05%module end holder set PEEK 169 56 9482 17.1 790 1.8 1.422 34.9 0.08%screws titanium 6 112 624 2.8 52 4.54 0.236 16.2 0.03%TIM btw ROC & substrate, 80% silicone 0.05 1394 56 56 3123 3.4 260 1.1 0.286 25.1 0.02%

TIM btw ROC & substrate, 20%boron nitrile 0.05 1394 14 56 781 2.7 65 3.5 0.228 43.4 0.01%

TIM for gluing the blades to rings, 80% silicone 0.05 58 2 28 65 0.1 5 1.1 0.006 25.1 0.00%TIM for gluing the blades to rings, 20%

boron nitrile 0.05 58 1 28 16 0.1 1 3.5 0.005 43.4 0.00%

Sub total % RL for substrate 0.54% HDI, kapton kapton 0.1 1141 114 56 6392 8.9 533 1.4 0.746 38.4 0.04%HDI, adhesive silicone 0.05 1141 57 56 3196 4.0 266 1.25 0.333 25.1 0.02%HDI, copper, 28% copper 0.057 1141 18 56 1020 9.5 85 9.3 0.791 12.9 0.12%Flex cable connector polyester 52 56 2917 4.1 243 1.4 0.340 28.7 0.02%Sub total % RL for HDI 0.20%  Outer outer tubing ss 316L 1114 0.49 545 1 545 4.3 45 7.82 0.355 14.1 0.05%Outer inner tubing ss 316L 493 0.49 241 1 241 1.9 20 7.82 0.157 14.1 0.02%Inner outer tubing ss 316L 832 0.49 406 1 406 3.2 34 7.82 0.265 14.1 0.04%Inner inner tubing ss 316L 501 0.49 245 1 245 1.9 20 7.82 0.159 14.1 0.02%Coolant for 4 tubing CO2 liq. 2939 1.62 2939 1 2939 3.0 245 1.03 0.252 36.2 0.01%TIM for filling up the groove, 80% silicone 1858 0.63 931 1 931 1.0 78 1.1 0.085 25.1 0.01%

TIM for filling up the groove, 20%boron nitrile 1858 0.63 233 1 233 0.8 19 3.5 0.068 43.4 0.00%

Coupling ss 304 61 6 366 2.9 31 7.82 0.239 14.1 0.03%Coupling titanium 43 6 260 1.2 22 4.54 0.098 16.2 0.01%Sub total % RL for tubing and coolant 0.19%   Outer outer ring CC 2 30476 1 30476 54.9 2540 1.80 4.571 42.7 0.20%Outer outer skin CF 0.56 8377 1 8377 14.7 698 1.76 1.229 42.8 0.05%Outer inner ring CC 2 8700 1 8700 15.7 725 1.80 1.305 42.7 0.06%Outer inner skin CF 0.56 2308 1 2308 4.1 192 1.76 0.339 42.8 0.01%Inner outer ring CC 2 17220 1 17220 31.0 1435 1.80 2.583 42.7 0.11%Inner outer skin CF 0.56 4523 1 4523 8.0 377 1.76 0.663 42.8 0.03%Inner inner ring CC 2 4985 1 4985 9.0 415 1.80 0.748 42.7 0.03%Inner inner skin CF 0.56 1322 1 1322 2.3 110 1.76 0.194 42.8 0.01%Inner mount tubing & inserts G10 973 3 2918 5.1 243 1.76 0.428 42.8 0.02%Inner mount screw aluminum 106 3 318 0.9 27 2.7 0.072 24.0 0.01%Outer mount insert G10 224 3 673 1.2 56 1.76 0.099 42.8 0.00%Outer mount screw aluminum 46 3 138 0.4 12 2.7 0.031 24.0 0.00%Sub total % RL for rings 0.54%  

  Total 397.6 33.1 1.94%

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Next Steps• Continue indium bonding R&D• Select proper TIMs for 4-blade thermal test

– Indium bonding R&D is in critical path• Practice production steps with developed tooling

– Glue module holders on module– Glue threaded inserts on TPG blade– Glue TPG blades on C-C rings to form bare half disk– Place and mount modules on TPG blades of bare half disk

• Conduct 4-blade thermal test• Design half cylinder• Pressure test of cooling coupling weldment assembly• Run cooling loop flow test with CO2 pilot plant

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Backup Slides

Cooling Tubing Layout……Original

• Outer Outer Tubing – 2 outlets from each half disk, located at 3 o’ clock position, inside HC• Outer Inner Tubing – 2 outlets from each half disk, 1at top + 1 at bottom, inside HC• Inner Assembly Tubing – 2 outlets from each half disk, at 3 o’ clock position, outside then inside HC

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Inner Outer & Inner Inner tubing connected in series

Outer Inner Tubing

Outer Outer TubingInner Assembly Tubing Outlets

Heat Load and Tube Lengths for 9 Cooling Loops of an FPix Half-cylinder (typical for each of 4 half-cylinders)

Cooling Loops for FPix Half-cylinder v3

19May2011* Nominal heat load per module 2.4 W, Power apportioned between O-O and O-I rings at an estimated 6:4 ratio

FPIX CoolingLoop

Heat load from

modules(t=0)[W]*

Heat loadfrom

DC-DC converters

[W]

Heat load from port

cards[W]

Heat load from cable losses

[W]

Total heat load

on cooling

loop[W]

Length of cooling loop on half-ringOD 1.6 mmID 1.4 mm

[mm]

Lengths of radial legs of cooling

loopOD= 1.6 mmID= 1.4 mm

[mm]

Lengths of longitudinal legs of loop near disk

OD = 1.6 mmID = 1.4 mm

[mm]

Length of loop heated by port cards or DC-DC

convertersOD = 2.0 mmID = 1.8 mm

[mm]

Lengths of longitudinal legs

of loop near manifold

OD = 2.0 mmID = 1.8 mm

[mm]

Fluid mass flow for

dP= 1.5 bar at -20 C

[g/s]130%

heat load

Fluid exit

quality[%]

130% heat load

HD1 O-O 49.0 0 7.5 5 61.5 1052 0 340+350 300 1784+1774

HD1 O-I 32.6 30 0 5 67.6 420 87+87 373+383 500 1784+1774

HD1 I-O & I-I 52.8 0 7.5 5 65.3 962 137+78+59 342+352 300 1784+1774 3.56 8.5

HD2 O-O 49 0 7.5 5 61.5 1052 0 296+306 300 1784+1774

HD2 O-I 32.6 30 0 5 67.6 420 87+87 265+275 500 1784+1774HD2 I-O & I-I 52.8 0 7.5 5 65.3 962 137+78+59 265+275 300 1784+1774

HD3 O-O 49 0 7.5 5 61.5 1052 0 168+178 300 1784+1774

HD3 O-I 32.8 30 0 5 67.6 420 87+87 201+211 500 1784+1774 5.0 6.2

HD3 I-O & I-I 52.8 0 7.5 5 65.3 1052 137+78+59 170+180 300 1784+1774Totals 403.2 90 45.0 45.0 583.2 38.5

1.4 mm ID tube in this region1.8 mm ID tube

4.2 m of copper tubing 10 mm ID

Welded with tubing

Welded with tubing

Replaceable aluminum gasket

M3.5 female thread nut

M3.5 male thread nut

CO2 Cooling Coupling Design

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gland

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CO2 Cooling Coupling Status

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Two sets of assemblies were laser-welded• Direct welding was done on gland • Welding rod 312 was used for male

thread nut because of larger part tolerance (0.005” vs. 0.002”)

Vacuum leak check was made on both assemblies

• No leak on aluminum washer sealing• No leak on gland weld• Leak on the male thread nut weld

Quick conclusion: Design and fabrication method OK, but needs tighter fitting tolerance

Weld for male threaded fitting

Weld for ferrule

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Couple of options for the revised cooling route within HC